Certain 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides are inhibitors of 3-lactamase and, when used in conjunction with β-lactam antibiotics, can be effective for the treatment of bacterial infections, e.g., by overcoming resistance mechanisms. See, for example, International Patent Application Publication No. WO2009/091856 which discloses 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and their synthesis from a ketosulfoxonium ylide intermediate containing an amide side chain, where the ylide intermediate is cyclized to a 5-oxo-piperidine-2-carboxamide using an Ir, Rh, or Ru catalyst. Similarly, Baldwin et al. disclose the transformation of lactone-derived β-ketosulfoxonium ylides into β-oxonitrogen heterocycles in the presence of a rhodium catalyst. See Baldwin et al., 1993, J. Chem. Soc., Chem. Commun. 18:1434-1435. Mangion et al. disclose iridium-catalyzed X—H insertions (e.g., N—H insertions) of sulfoxonium ylides. See Mangion et al., 2009, Org. Lett., 11:3566-3569 and Mangion et al., 2011, Org. Lett. 13:5480-5483.
U.S. Patent Application Publication No. US2003/0199541 discloses methods for preparing azabicyclic compounds which are useful as medicaments, in particular anti-bacterial agents. International Patent Application Publication No. WO2008/039420 discloses methods for preparing certain 7-oxo-2,6-diazabicyclo[3.2.0]heptane-2-carboxamides which are useful as β-lactamase inhibitors.
U.S. Pat. No. 6,924,327 and Wang et al., 2004, J. Org. Chem. 69:1629 describe the use of trimethylsulfoxonium iodide to prepare chloroketones. International Patent Application Publication No. WO2010/126820 discloses the preparation of alkyl esters of N-protected oxo-azacycloalkylcarboxylic acids. These esters can be used as intermediates in the synthesis of 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and esters. International Patent Application Publication No. WO2014/200786 discloses the preparation of N-protected 6-(piperidin-4-ylcarbamoyl)piperidin-3-yl sulfonates. These sulfonates are suitable for use as intermediates that lead via a series of additional process steps to the synthesis of 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and esters. U.S. Patent Application Publication No. 2015/0141401 describes processes and intermediates useful for the synthesis of beta-lactamase inhibitors.